Capture plot, save it in memory and display it in lcd

I am currently developing an app in android that sends a string to a bluetooth module HC06 and is picked up by a pic 16f883.

I created an interruption that makes it appear on the lcd when the plot arrives, but I do not know how I can capture it, save it in a buffer and this in turn stores it in memory.

#include <16F883.h>
#fuses HS,NOWDT,PROTECT,NOLVP
#use delay(clock=20000000)
#use  rs232(baud=9600, xmit=PIN_C6,rcv=PIN_C7)

#include <flex_lcd.c>
#include <stdlib.h>

//FUNCIONES
void inicio();

//VARIABLES
char mivariable;
int i;
int contador=1;

//INTERRUPCION
#INT_RDA   // Interrupccion  USART
void RDA_isr()
{
    output_high(pin_A2);
    if(contador==16){
        contador=1;
        printf(lcd_putc, "f");
        lcd_gotoxy(1,1);
        printf(lcd_putc,"BLUETOOTH_2");
    }
    mivariable = getc();

    lcd_gotoxy(contador,2);
    lcd_putc(mivariable);
    contador++;
    output_low(PIN_A2);
}

void main()
{
    inicio();
    while (true)
    {

    }
}

//INICIO LCD CON CARGA....
void inicio(){
    enable_interrupts(INT_RDA);
    enable_interrupts(GLOBAL);
    delay_ms(100);
    lcd_init();
    output_high(pin_A2);
    lcd_gotoxy(1,1);
    printf(lcd_putc, "Loading");
    for(i=1;i<=16;i++){
        lcd_gotoxy(i,2);
        printf(lcd_putc, "*");
        delay_ms(200);
    }
    printf(lcd_putc, "f");
    lcd_gotoxy(1,1);
    printf(lcd_putc,"BLUETOOTH_2");
    output_low(PIN_A2);
}